[Aerobic nitrifying granulation fed with source-separated urine in sequencing batch reactor].

Morphological characteristics of aerobic nitrifying granules that were utilized to treat the diluted source-separated urine were investigated in two lab-scale sequencing batch reactors. In the first sequencing batch reactor, which was inoculated with nitrifying bacteria, the COD of effluent was markedly decreased while the nitrification rate was very low. Aerobic nitrifying granules were not appeared in the first bioreactor. In the other SBR system that was inoculated with aerobic granules cultivated in the laboratory, the COD and ammonia in source-separated urine were effectively removed and the removal rate was more than 90%. Under operational condition that influent ammonia volume rate was 0.5 kg/(m3 x d) for 70 days, the aerobic nitrifying granules were stable in the reactor. Aerobic nitrifying granules have well settleability and metabolize activity, the surface of granules was occupied by nitrifying bacillus and cocci bacteria. Contrast to the inoculating aerobic granules, the diameter of aerobic nitrifying granules dramatically decreased to more than 2 mm and the settle velocity were greater than that of aerobic granules which have the same diameter.